The normal plugging agents used for drilling in oil extraction are made of walnut shell, shell power, mica sheet and husk and have made great contribution to oil extraction. However, following shortcomings exist. (1) The effect is bad. (2) Large quantity of plugging material and long operation time are required. (3) Such agent will seriously damage pump parts, causing complex drilling troubles. (4) Such combination is only capable of permeable leakage caused by small and medium-sized cracks and porous formations but incapable of large scale leakage. (5) The walnut shell of large rigidness and no elasticity easily gathers at the entrance of the leaking pipe other than letting large granules get into the pipe deeply, thus it only seals the pipe tentatively and will cause repeat leakage latter, leading to major economic loss and greatly impacting on the plugging effect and drilling project.